I. Field of the Invention
The invention relates to a method of forming a precision pulley wheel and, more particularly, to forming a pulley wheel secured by laser welding and encompassing a unique hub assembly.
II. Description of the Related Art
Pulley wheels are well known for use with belts such as V-belts. Generally, the pulley wheels are manufactured from a pair of stamped disk members formed from sheet metal by stamping operations on a punch press with various configurations. The disk members can include angularly spaced spoke portions connecting inner and outer annular portions thereof. The disk members are secured together, back to back, forming an outer annular belt receiving groove and are spot welded or otherwise secured to a central hub member.
The disk members are secured together by various methods that have been found to have many disadvantages. In the split steel method, the sheet metal disc is clamped on a rotating shaft after which a hard steel roller force splits the material which is then formed into shape. The high pressure resulting from the process creates extreme heat conditions causing deformation and crystallization of the metal. The result is that the manufactured pulley wheels are not true running and the manufacturing process is slow and expensive.
In the brazing method, the disk members being secured together are subjected to the extreme heat of a brazing furnace which causes distortion of the metal. The result is that there is a high percentage of breakage due to inconsistency of the material, the process is expensive to run and the pulley wheels are not true running.
In the method combining resistance welding and brazing, the disk members are spot welded together and the hubs are brazed to washers and the washer projections are welded to the pulley wheel. The result is that there is a large amount of distortion and breakage of the metal, the process is expensive and the pulley wheels are not true running.
The manufacture of pulley wheels is known to be an extremely competitive industry. There is a continuous need for improved methods which will improve the durability of the pulley wheel, decrease the manufacturing costs and produce a true running pulley wheel.
As can be readily ascertained from the foregoing, various improvements in the method of manufacture and construction of pulley wheels are desirable.
It is a general object of the present invention to provide an improved method for manufacturing pulley wheels.
It is a particular object of the present invention to provide improved pulley wheels.
It is a further object of the present invention to provide a method of manufacturing pulley wheels which eliminates the use of high temperatures which causes deterioration of the metal.
It is another object of the present invention to provide a method which will increase the durability of the pulley wheels.
It is another further object of the present invention to provide an improved method of securing a hub to the pulley wheel.
It is yet another object of the present invention to provide a method which will reduce the cost of manufacturing the pulley wheels.